Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

The Electrical Double Layer01:30

The Electrical Double Layer

In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
Metal-Semiconductor Junctions01:24

Metal-Semiconductor Junctions

The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Carrier Generation and Recombination01:22

Carrier Generation and Recombination

Carrier generation is the process by which electron-hole pairs (EHPs) are created within the semiconductor. In direct-bandgap semiconductors, such as gallium arsenide (GaAs), this occurs efficiently when energy absorption prompts valence electrons to leap into the conduction band, leaving behind holes.
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
Interfacial Electrochemical Methods: Overview01:06

Interfacial Electrochemical Methods: Overview

Interfacial electrochemical methods focus on the phenomena occurring at the boundary between an electrode and a solution, as opposed to bulk methods that concentrate on the solution's overall properties. These interfacial methods are classified as either static or dynamic based on the presence of a nonzero current in the electrochemical cell and the consistency of analyte concentrations. Static methods, such as potentiometry, measure the cell's potential without any significant current passing...
P-N junction01:11

P-N junction

A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Electrostatic Interaction across a Single-Layer Carbon Shell.

The journal of physical chemistry letters·2018
Same author

Formation of two-dimensional polarons that are absent in three-dimensional crystals.

Physical review letters·2007
Same author

Electron dynamics at polyacene/Au(111) interfaces.

The journal of physical chemistry. B·2007
Same author

Electron transport across the alkanethiol self-assembled monolayer/Au(111) interface: role of the chemical anchor.

The journal of physical chemistry. B·2006
Same author

Delocalized electron resonance at the alkanethiolate self-assembled monolayer/Au(111) interface.

The Journal of chemical physics·2006
Same author

Randomised evaluation of alternative electrosurgical modalities to treat bladder outflow obstruction in men with benign prostatic hyperplasia.

Health technology assessment (Winchester, England)·2005

Related Experiment Video

Updated: Jun 23, 2026

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
11:44

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Published on: October 18, 2018

Charge-transfer excitons at organic semiconductor surfaces and interfaces.

X-Y Zhu1, Q Yang, M Muntwiler

  • 1Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA. zhu@umn.edu

Accounts of Chemical Research
|April 22, 2009
PubMed
Summary

Charge-transfer excitons in organic solar cells are strongly bound. Hot charge-transfer excitons, not the lowest energy states, are key for efficient charge separation and device performance.

More Related Videos

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
08:04

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds
09:45

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Published on: December 2, 2013

Related Experiment Videos

Last Updated: Jun 23, 2026

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
11:44

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Published on: October 18, 2018

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
08:04

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds
09:45

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Published on: December 2, 2013

Area of Science:

  • Materials Science
  • Physical Chemistry
  • Organic Electronics

Background:

  • Excitons, or bound electron-hole pairs, form when photons excite low dielectric constant materials.
  • Charge-transfer (CT) excitons form at donor/acceptor interfaces in organic solar cells, with binding energies significantly exceeding thermal energy (k(B)T).
  • The dissociation of these strongly bound CT excitons presents a challenge for efficient photovoltaic energy conversion.

Purpose of the Study:

  • To investigate the mechanism of electron-hole pair escape from Coulomb traps in organic heterojunction solar cells.
  • To identify the specific exciton states involved in efficient charge separation at donor/acceptor interfaces.
  • To propose a design principle for enhancing organic solar cell performance based on exciton dynamics.

Main Methods:

  • Utilized a crystalline pentacene thin film as a model system.
  • Employed time-resolved two-photon photoemission spectroscopy to observe charge-transfer excitons.
  • Analyzed exciton binding energies and quantum numbers using an atomic H-like Schrödinger equation model.

Main Results:

  • Observed charge-transfer excitons with binding energies up to 0.5 eV below the image band minimum.
  • The lowest energy CT exciton (CT(1s)) exhibited a binding energy over an order of magnitude greater than k(B)T, indicating low dissociation probability.
  • Identified 'hot' CT exciton states as more weakly bound and more easily dissociated compared to CT(1s) states.

Conclusions:

  • Hot CT exciton states, rather than the ground state CT(1s) exciton, are crucial for charge separation in organic solar cells.
  • These hot excitons facilitate dissociation due to weaker Coulombic binding and increased density of states.
  • Strong electronic coupling between molecular excitons and hot CT excitons across the donor/acceptor interface is a key design principle for efficient organic heterojunction solar cells.